Choose a waterproof electrical box with a high IP rating, like IP66 or IP67, for reliable protection against heavy rain and humidity. Replace worn parts to maintain a tight seal. Severe weather can harm your outdoor power distribution box. Rain, snow, and wind can damage it, making your electrical system unsafe. Follow these five steps for a secure install: Pick the right spot. However, they are exposed to harsh weather elements such as rain, snow, and humidity, which can cause moisture buildup inside the outlet.